Neurology Unit, Unita Sanitaria Locale of Viareggio, Viareggio, Italy.
J Clin Exp Neuropsychol. 2011 Apr;33(4):395-409. doi: 10.1080/13803395.2010.524150. Epub 2010 Dec 6.
Cognitive impairments are common in patients with Parkinson's disease (PD) from the early stages. Recent studies reported that medicated PD patients have poor performances, with respect to age-matched healthy controls, in a decision-making task like the Iowa Gambling Task (IGT), which detects the ability to alter choice behavior in response to fluctuations in reward contingencies. The IGT principally activates functions related to the orbitofrontal cortex, which plays a crucial role in the generation of outcome expectancies and processing of rewards. The analysis of IGT performances of PD patients is of particular interest because PD represents a good clinical model to study reward processing when its neural bases are affected by a neuropathology or are overdosed by dopaminergic therapies. As a matter of fact, either PD-related neuropathology in advanced stages of the disease or the dopamine replacement therapy from earlier stages of PD may affect the functioning of the orbitofrontal cortex. Three causal hypotheses on a dysfunctional decision making in PD patients, as assessed by IGT, are discussed. Finally, the possible relation between the phenomenon of decision-making impairment and impulse control disorders, a psychiatric complication observed with increasing frequency in PD patients, is discussed.
认知障碍在帕金森病（PD）患者的早期阶段很常见。最近的研究报告称，在像赌博任务（IGT）这样的决策任务中，与年龄匹配的健康对照组相比，接受药物治疗的 PD 患者表现不佳，该任务可检测出根据奖励变化改变选择行为的能力。IGT 主要激活与眶额皮层相关的功能，眶额皮层在产生结果预期和处理奖励方面起着至关重要的作用。分析 PD 患者的 IGT 表现特别有趣，因为当神经病理学影响其神经基础或多巴胺能治疗过度时，PD 代表了研究奖励处理的一个很好的临床模型。事实上，无论是疾病晚期的 PD 相关神经病理学还是 PD 早期的多巴胺替代疗法，都可能影响眶额皮层的功能。讨论了通过 IGT 评估的 PD 患者决策制定障碍的三种因果假说。最后，讨论了决策障碍现象与冲动控制障碍之间的可能关系，冲动控制障碍是 PD 患者越来越频繁观察到的一种精神并发症。
